The disclosures herein relate generally to portable computers and more particularly to a torsion bar connected to hinge brackets mounted in a top portion of a portable computer.
As LCD screens for portable computers increase in size, the thickness and weight that is expected of the portable computers is decreasing. When the user opens or closes the top portion of the portable computer, usually one corner of the top portion is pulled or pushed and pivoted relative to a base portion. The top portion is stiff enough to overcome the friction torque of the hinge on the side that is pulled/pushed. However, the LCD panel mounted in the top portion is not stiff enough to overcome the torque at the hinge on the opposite side of the LCD panel from where the user applied the force. The top portion has a tendency to twist from the torque applied. This twist applies a torque to the LCD panel causing it to twist. A twisted LCD panel can experience various levels of problems such as LCD ripple, i.e. a distorted screen which resembles water ripples, pixels failing due to twisted glass, lines of pixels failing, and customer dissatisfaction.
This has been an issue with portable computers for a long time. There have been two main solutions that have been used to solve this problem including increasing the thickness of the top portion, and using metal brackets which support the top portion. Both of these solutions add thickness and weight to the portable computer. A problem is that these solutions don""t address true the problem in the most analytical way; they only attempt to out muscle the torque imposed on the hinges.
In U.S. Pat. No. 5,379,183, the lid portion of a notebook computer is pivotally secured to the base portion of the computer using an elongated metal hinge structure directly interconnected between the lid portion and the metal I/O plate disposed at the back side of the computer base portion and grounded to the system planar board therein. A direct grounding connection is thus formed from the lid portion to the system planar board through this combination I/O plate/lid hinge structure.
Therefore, what is needed is a load bearing apparatus and system that equally distributes load between the separated hinges so that the top portion and LCD panel do not carry the load imposed by a force exerted on one corner of the top portion.
One embodiment, accordingly, provides a torsion bar extending between the spaced apart hinge brackets. To this end, a portable computer includes a base and a cover pivotally connected to the base for movement between a closed position and an open position, the cover includes a free end and a pivotally connected end. A hinge component includes a first portion and a second portion mounted in the pivotally connected end of the cover between a first side and a second side of the cover, respectively. A torsion member interconnects the first and second portions of the hinge component. The torsion member has a closed cross-section.
A principal advantage of this embodiment is that the torsion bar provides adequate stiffness to the LCD panel and cover without a substantial increase in weight.